There is no paucity of surfactants and builders for use in detergent compositions per se. However, the most widely used detergents for home laundry use, use linear alkyl-benzene sulfonates (LABS) or alcohol ethoxylates as detergent and sodium tripolyphosphate STPP as a builder. The use of sodium tripolyphosphate (STPP) as a builder has drawbacks for example the presence of phosphate in rivers and lakes causes eutrophication. Similarly the biodegradable ethoxylated alcohols are relatively costly compared to their precursor alcohols and, while effective against soiled synthetics, are borderline for the laundering of cellulosics such as cotton.
In view of the different characteristics now required of detergents such as good biodegradability, compatibility with other detergents, builders, good launderability against both natural and synthetic fabrics, as well as low mammalian toxicity and the like, the development of multifunctional detergents combining several of these properties can represent a distinct advance in the art.
Recently, the applicants have discovered that certain polycarboxylic acids containing 3 or 4 unesterified carboxylic acid groups on a saturated aliphatic chain are good detergent builders when combined with other detergents and/or builders. For example, these polycarboxylic acids in the form of their sodium salts were evaluated as builders with standard detergents such as linear alkylbenzene sulfonate (LABS). As shown in subsequent data, the detergent building properties of all 6 illustrative polycarboxylic acids exemplified are equal or superior to sodium tripolyphosphate (S.T.P.P.) or citric acid.
The monodecyl esters of the polycarboxylic acids can function as to a limited degree as surfactants in addition to being builders. Thus, they show promise as combination detergent-builders with LABS.
Data presented below show that the monoesters as builders are superior to STPP. As surfactants, when formulated with STPP the esters are generally superior to normal paraffin sulfonate (NPS) but are less effective generally than (LABS) on cotton test cloth. In general, the monodecyl esters are less effective in tests performed on synthetic fabrics.